Friction draft gear



lMHyZE, 1923.

- E. C. WASHBURN FRICTION DRAFT GEAR Filed Feb. 5,

my 2 W 5 Maw. ,m 1% i Patented July 24, 1923.

inear EDWIN c. wnsneuan, or nneLnwoon, new JnnsnY.

FRICTION DRAFT GEAR.

Application filed February 5, 1921. Serial No. 442,658.

T 0 all whom it may concern:

Be it known that I, EDWIN C. VVAsHBUnN, a citizen of the United States, residing at Englewood, in the county of Bergen and State of New Jersey, have invented certain new and useful Improvements in Friction Draft Gears; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to a friction draft gear, particularly to such a device designed for use with railway cars. It is now the practice to equip railway cars of practically all types with some form of spring or fric tion draft gear to absorb the shock occasioned by starting and stopping the train and to relieve the car structure from strains'incident thereto. Many of the friction draft gears in use are of complicated structure requirin many parts and thus resulting in greatly added weight.

It is an object of this invention to provide a friction draft gear of few parts which will be of light weight, inexpensive and yet very etlicient for the purposes had in view, and which will be efficient in operation to withstand the maximum strains and shocks usually occurring in railway operation.

It is a further object of the invention to provide a draft gear having a combined friction and spring element, the spring and friction feature of which are successfully brought into operation. 7

It is also an object of the invention to PTO-1 vide a novel reinforcing means for the enclosing strap or yoke used with the'friction draft gear.

These and other objects and advantages of the invention will be apparent from the following description made in connection with the accompanying drawings in which like reference characters refer to the same parts throughout the different views, and in which,

Fig. 1 is a longitudinal section of the draft gear taken on the line 11 of Fig. 2;

Fig. 2 is a view in side elevation of the draft gear, as shown in Fig. 1;

Figs. 3 and 4; are partial sectional views similar to Fig. 1, showing the gear in successive stages of compression; and

Fig. 5 is a transverse section taken on-the line 55 of Fig. 1.

Referring to the drawings, the gear is shown as enclosed in longitudinal channel members 1 which are suitably secured to the car structure and terminate in the car sills at their forward ends. These members are connected at one end by channel members 2 which form the abutment for a back plate 3 and the members 1 are also connected by upper and lower channel members 3 forming a supporting means for parts of the draft gear. The channel members 1 are reinforced at the sides by plates 4 having elongated th1ckened portions or bosses at their central portions through which are formed enlongated slots 5. A bar 6 of oblong or elongated elliptical cross section is secured in the head member 6 and has its ends projecting throughthe slots 5. The head member 6 abuts at its front end withthe end of the coupling head or drawbar member 7 and has a terminal projection extending into with raised portions or bosses surrounding the slot receiving the bar 8, and these members 10 are preferably cast about or on the ends of the yoke member 9 so as to be more or less integrally connected thereto. The

'yoke member 9 'carries at its closed end a buffer plate 11 provided, with a central recess or slot extending centrally thereof, which slot is of greater depth than the thickness of the yoke?) so that the rear surface of the yoke will not come into contact with the plate 3 Disposed between the buffer plate 11 and the head member 6 is a volute plate spring 12 comprising several convolutions which are stepped relative to each other, or formed in the shape of a helix.

The inner and outer ends of this spring are tapered in thickness, as shown in Fig. 5.

Disposed within the inner convolution of the spring 12 are a plurality of blooksl?) having their outer surfaces curved and having their inner surfaces plane and converging at the longitudinal center thereof. In the embodiment of the invention illustrated, eight of these blocks are shown and a pair I of oppositely disposed octagonal wedge members 14 being pushed together.

head member 6 is provided with a raised central portion at its inner end which is, in turn, provided with a conical raised portion 16 over which the outer wedge member 14 is adapted to fit. The buffer member 11 is provided on its face opposite the spring, with a circular unstanding projection adapted to fit within the inner convolution of the spring.

The operationof the device is as follows 1 Assuming. that a sudden pulling stress is placed upon the coupling head 7, this stress will be transmitted to the yolre'member 9 by the bar 8 and through the spring wedges tothe bar 6, and thence to the members 1 and the car body; The shock occurring owing to the inertia of the car mass, will first be taken by the spring 12 and the yoke member 9 will move relatively to the member 6 and compressithe spring 12 and thus tend to bring all of the convolutions thereof into alinement. lVhen the spring has been suliiciently compressed to take up the space between the buffer members 11 and the adjacent .wed ge member 14, any further movement will result in the wedge This will spread the wedge blocks 13 which will engage with the inner convolutions of the spring and begin to expand the spring from the inner side outwardly. If the stress is sufficient the movement will continue until be still further augmented by the friction of the various convolutions of the spring on each other as the sprlng is expanded. It will thus be seen that the draft gear uti- ,li'zes the combined spring and friction action of the volute spring 12 as well as the aditional friction of the wedge members.

llVhen the stress is relieved, the spring 12 will gradually assume its normal shape and will separate the members 6 and 11. When thestress is placed on the car by a sudden movement in the opposite direction, the bar 6 will travel in the slot 8, the buffer plate 11 contacting with the abutment member 3*. The device is designed to operate in a compression movement of substantially 2-} inches, the clearance in the slots in the side member 1 and the drawbar allowing for approximately 25}; inches of movement which isthe distance specified by the Master Car Builders Association.

The projection 16 is formed to engage the outer wedge member 14 so thatthe same will be prevented from dropping down out of place, the other member 14 being held in position-by the spring. It will be noted that by enclosing the end of the yoke member 9 by the buffer plate 11 the back end of the yoke will not be repeatedly pounded against the back plate3 theimpact being taken by member 11. This will avoid crystallization. of the metal of the yoke and pre vent untimely breakage thereof.

From the above description it is seen that applicant has invented a friction draft gear of few and rugged parts whichare of comparativcly simple construction, the operation of which is positive and certain, The draft gear, as a whole, is quite light and yet the parts are of sufficient strength/to sufficiently cope with the maximum stress encountered. In actual tests the device is found to operate very successfully and to successfully handle exceedingly large stresses. .he parts are preferably made of steel, although it will be understood that other material may be used if found desirable in practice.

It will, of course, be understood that various changes may be made in the form, de-

tails and proportions of the device without departing from thescope of applicants invention, which, generally stated, consists in the matter shown and described and set forth in the appended claims.

What is claimed is: p 1. A draft gear having in combination a longitudinal compressible volute plate spring, means for compressing said spring and frictional radially movable means for expanding the same. v

2. A draft gear having in combination a volute plate spring and. friction means engaging the inner surface thereof and radially movable for expanding the same.

3. A. draftgear having in' combination, spaced follower plates, a longitudinally compressible volute plate spring disposed there-between, oppositely disposed wedge members between said plates, and a plurality of circumferentially arranged wedge blocks having diverging wedge surfaces at each end, respectively, contacting said wedge members and having outer surfaces contacting the inner surfaces of said spring.

4;. A. draft gear having in combination a volute plate springpfrictional means enclosed thereby for expanding the same, and

frictional means engaging said first 'men tioned frictional means tomove the same radially to expand said'spring.

5. A draft gear having in combination spaced follower plates, spaced opposltely disposed wedge members contacting said follower plates and adapted to be moved thereby, a series of wedge blocks: disposed about said wedge members, and a volute plate spring enclosing said blocks and engaging the entire cylindrical surfaces thereof.

(3. A draft gear having in combination spaced follower plates, a longitudinally compressible volute spring disposed between and normally contacting said plates, expansible friction means disposed in said spring between said plates normally spaced from one of the same, whereby, when said plates are moved together, the spring will first be compressed longitudinally and will then be expanded by said friction means being engaged and actuated by said plates.

7. A draft gear having in combination spaced follower plates, a longitudinal compressible volute spring arranged therebetween, oppositely disposed wedge members disposed between said plates and a series of wedge blocks circumferentially arranged about said wedge members enclosed by and frictionally engaging the inner surface of said spring and frictionally engaging the outer surfaces of said wedge members.

8. A draft gear having in combination spaced follower plates, a longitudinal compressible volute spring disposed therebetween, oppositely disposed wedge members also disposed between said plates, means connecting said wedge members, and a series of Wedge blocks circumferentially arranged about said wedge members and enclosed by said spring. 7 Y

9. A draft gear having in combination a volute plate spring, a series of wedge blocks having their outer surfaces arranged with their circumference contacting the inner surface of saidspring and having their inner surfaces formed with plane surfaces converging toward the longitudinal center, and oppositely disposed wedge members disposed in said series of wedge blocks and having a plurality of plane surfaces thereon engaging the inner plane wedge blocks.

10. A draft gear having in combination a volute plate spring, and radially movable expanding means contained within the same for expanding said spring and having cylindrical surfaces frictionally engaging substantially the entire inner surface of said spring.

11. A draft gear having in combination a volute plate spring and segmental wedges disposed inside of the convolutions thereof and having surfaces engaging substantially the entire inner surface of said spring for expanding said spring against the tension thereof and the friction of the convolutio-ns, one on the other.

In testimony whereof I affix my signature.

EDWIN o. WASHBURN.

surfaces of said 

